Finger-operable liquid dispensing pumps are typically adapted to be mounted on hand-held containers. Such containers are commonly used for liquid products, such as household and automotive cleaners, industrial preparations, and personal care products such as hairsprays, deodorants, colognes, and the like. Typically, the pump is operated to produce a fine mist or atomized spray.
Finger-operable pumps conventionally employ a pump chamber in which is disposed a pressurizing piston that can be actuated by pressing down on an external actuator button or plunger. A spring acts against the piston or actuator button to return the piston and actuator button upwardly to the elevated rest position when the finger pressure is released.
Typically, a valve member is provided within the pump and is biased by a spring to close a discharge passage at a valve seat. This permits a predetermined pressure to be built up within the pump chamber as the pump actuator is pressed downwardly. When the pressure force within the pump chamber exceeds the valve member spring biasing force, the valve member opens to permit discharge of the pressurized liquid from the pump chamber.
The discharging liquid exits the pump through a nozzle as a jet stream, a coarse spray, an atomized fine spray, etc., depending upon the structure of the nozzle, operating pressures, stroke speed, and characteristics of the liquid being dispensed.
Some pump designs are especially suitable for producing an atomized fine spray of liquid. The manufacturer of the liquid may desire that it be dispensed in a substantially fully atomized spray condition so as to produce a relatively fine mist. Typically, conventional pumps designed for producing a fine mist work well only if operated in a certain manner (e.g., typically through a full, or complete, stroke at a stroke speed exceeding a predetermined minimum stroke speed).
For example, if the pump operator slows the compression stroke below a certain speed or temporarily stops the compression stroke, then the desired discharge spray is not produced. Rather, a more coarse spray may be produced than is desired.
Further, manufacturers of some liquid products may have a desired or recommended dose or quantity of product which is to be dispensed with each actuation of the pump. The quantity to be dispensed depends on the length of the pump stroke prior to release of the finger force. If the finger is released from the actuator prior to the completion of the full pump stroke, then the quantity of the discharged product will be less than is intended or desired by the manufacturer.
It would be desirable to provide an improved design which operates as intended substantially independently of the range of the typical force or movement of the operator's finger. It would also be advantageous if such an improved system produced a fine mist spray without the application of excessively high forces to the pump actuator.
It would also be desirable if such an improved system could accommodate initial priming of the pump chamber while exhausting air through the discharge orifice in an efficient manner.
Further, it would also be beneficial if the improved system could be incorporated in a pump having a minimum final volume at the end of the compression stroke so as to effect efficient priming of the system and a more rapid return of the pump actuator during the return stroke.
It would also be desirable to provide an improved design which could accommodate a relatively short stroke so as to permit a reduction in the overall pump height.
Preferably, a pump incorporating such improved design features should also perform consistently with respect to the discharge particle size and the required actuation force as well as with respect to the quantity of discharged product per full stroke actuation.
Advantageously, such improved design features should also be readily incorporated in the pump and in components therefor so as to facilitate economical manufacture, high production quality, and consistent operating parameters unit-to-unit with high reliability.
The present invention provides an improved pump valve system and pump which can accommodate designs having the above-discussed benefits and features.